Scams have been around forever, but our modern world has seemed to bring out a whole new class of scammer that trades less in verbal flim-flam than high-tech savvy. The latest scam utilizes a technique called “spoofing,” which allows a caller to change their telephone ID and mislead the recipient of the call about who is on the other line.

Using the technique, dozens of Bay Area residents have received calls on their cell phones in recent days identifying the caller as “911 emergency,” or some variation. Scammers impersonating police officers then try to elicit personal information or wrongly tell the call’s recipient that there is a warrant out for their arrest or there is an emergency at their home. Officials are investigating the calls and trying to figure out exactly what the scammers are up to.

While the 911 spoofing calls appear to be a new installment in the scammers’ Hall of Shame, there is a long history, in the Bay Area and elsewhere, of thieves running sophisticated and damaging scams. In one, unsuspecting people, often seniors, are targeted on the street and persuaded to take large amounts of money out of their bank accounts and hand it over, under a complicated cover story about the cash being needed to free up a larger store of cash, which the scammer promises to split with his victim. Sometimes the deception is simpler — a person wearing an official-looking utility uniform shows up at peoples’ homes pretending to be with the gas company or the water department. Once allowed in the home, they search out money, jewelry or other items while the victim is distracted.

It’s good to remember a couple of key rules: Never give out personal information, such as social security numbers or bank account information, over the phone. And never allow surprise visitors from the “water department” into your home — such visits are always scheduled in advance. Using common sense will decrease your chances of being scammed.